. I BOOM \ "i NOBTB PA( DTK a\i> MM \ - i iflju 



i 



P[ua rhu Vmwmu i . Kmet J. .urn 8 



/'i- . (id \ i iiiiii i , Shall 



Bg 

 ■rr jUttipinu* Vbrbi 



A usually thick-rayed Pilaster with nun • 



tted abactinal spines arranged in a very irregular reticul and 



lateral surface of rays, or in detached convex grou] dry on outer pari "f 



mil Bpinea longer than the abactinals, clavate, striate, in upward • iili- 



iimI * Furcate pedicellariae with the undivided basal portion of jai 



equal in length to the longer <>f th<' two hyaline b hich has the Mppor odge 



decidedly uneven in most cases). I'l 7t, \\^<. 1. - 



/'. er ptiot The species i- so variable that a compos 

 ble. There are three fairly well marked formae which fr* 



■ have been heretofore ranked as spot 



fornuo, II RA< I I - Hr.nJi 



J PlgriN 1; Plate 74,1 



This foim standi between eonfertus, with unaU spinlete, an I 

 by Btout Bubglobose abactinal tubercles in ited convex group 



heaps. It is assumed to be the typical form, and il was 3 mpson when 



he described conjertvu as a distin rhe onlj sp< im from 



i. the type locality, examined by mi' (pL SI, i this forma. 



janthina Brandt, also described from Sitka, is a am- 



mon purple phase of onspicuo • Departure] i Columbi 



An average specimen from Monterey Kay measures K mo nun . : 10 mm., breadth 

 iv at base, to mm. Specimens reach twice this length of ray; rays may !><• 

 \ broader. Sitka example: K L 15 mm., r 36 mm., breadth of raj mm. 



[Tie 'li-l. i- normally convex or rather high arched owing to I 



■im'; the raj hed, normally Bubcircular in Lion; thi 



surface, viewed from below, dopes downward to the border of the narrow ambulacra] 

 furrow, which broaden aburptly at base of ray. The abactinal 

 on the side of the ray. the Buperomargina] phi: • noar the actina 



I from the inferomarginals by a relatively narrow but well-defined channel. 

 The entire skeleton is very robust and riu'id. the dorsal forming an irregular retii iluin 



• ither side of the rather irregular carina] - rhe skeletal ridges are ; 



up of very numerous small irregular plat* (real vari 



lyers thick in mature specimens, hound together by extremely tough tiss 

 intervals are sunken, and are subdii ided by much lower trabecular nol externally 

 visible even in dried examples unless treated with caustic potash 

 ondary trabecular tual intervals of the akolet 



■ •f papula Among these and 



the [her ridgi - are i erj nun!' 



iriae, the latter predominating in n 



